subroutine rks1
use var
implicit none

    integer i,m,j
    real(8) du,dv
    real(8) Qmean_n_k(1:gridsx,1:gridsy,5)
    
        
    call comput_Qx_p_Qx_m
    call comput_Qy_p_Qy_m    
    call Glf(gridsx,gridsy)
    call rhs(Qmean,Qmean_n_k)
    do j=1,gridsy
        do i=1,gridsx
            Qmean(i,j,1)=Qmean_n(i,j,1)-dt*Qmean_n_k(i,j,1)     
            !
            !write(*,'(I4,I4,2X,100(ES12.4,1X))') i,j,Qmean_n_k(i,j,1)
            Qmean(i,j,2)=Qmean_n(i,j,2)-dt*Qmean_n_k(i,j,2)
            
            Qmean(i,j,3)=Qmean_n(i,j,3)-dt*Qmean_n_k(i,j,3)
            
            Qmean(i,j,4)=Qmean_n(i,j,4)-dt*Qmean_n_k(i,j,4)
            
            Qmean(i,j,5)=Qmean_n(i,j,5)-dt*Qmean_n_k(i,j,5)            
               
        enddo         
    end do
    call comput_original_var
    call boundary
    

end subroutine 